Rotary displacement device



Jan. 20, 1942. c, BANCROFT 2,270,493

ROTARY DISPLACEMENT DEVICE Filed May 17, 1940 s Sheets-Sheet 1 29| 27 J I Q 9 wt /;,g 76 h ATTORNEYS Jan. 20,- 1942. c. BANCROFT ROTARY DISPLACEMENT DEVICE 3 Sheets-Sheet 2 Filed May 17, 1940 INVENTOR; 6776 184615 fifl/VCZQOFT' ATTORNEYS Jan. 20, 1942. Q BANCROFT 2,270,493

ROTARY DISPLACEMENT DEVICE I Filed May 17, 1940 3 Sheets-Sheet 3 sY /7 w ATTORNEYS Patented Jan. 20, 1942 UNiTED STATES PATENT OFFICE 19 Claims.

This invention relates to rotary displacement devices and more especially to rotary displacement devices of the alternately accelerating piston type, such as disclosed in Bancroft Patent No. 2,132,596.

An object of this invention is a device of the type above described which is of improved operational characteristics and of simplified construction.

Other objects, novel features and advantages of this invention will become apparent from the following specification and accompanying drawings, wherein:

Fig. 1 is an axial section through one embodiment of the invention;

Fig. 2 is an exploded perspective View of a portion of the device;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a perspective View of a portion of the device;

Fig. 5 is an axial section through a modified embodiment of the invention;

Fig. 6 is a section on the line 66 of Fig. 5;

Fig. 7 is an exploded perspective View of a portion of the embodiment of Fig. 5;

Fig. 8 is a perspective view of another portion of the embodiment of Fig. 5, and

Fig. 9 is a fragmentary section on the line 9-9 of Fig. 8.

Referring now to Figs. 1 to 4 inclusive, in

which the invention is disclosed as embodied in a displacement device having two sets of rotary pistons, a generally cylindrical casing I is provided with end plates H and 12 to form a housing, the end plates being clamped to the casing by suitable bolts 13, The casing has two sections of different diameter, thereby forming an annular interior surface Illa. A crank shaft 14 having a crank pin I is journalled in the housing. For assembly purposes, the crank shaft is constructed in two sections with the junction of the two sections being embodied in the crank pin. The end plate H is provided with a recess in which is arranged an anti-friction bearing supporting the hub of the crank shaft counterweight 16 into which is fitted one end of the crank shaft and the other end of the crank shaft is journalled in the hub [2a of the plate l2. A member l1, hereinafter referred to as the connecting member, is rotatably supported by the crank shaft I d concentric with the crank pin l5 by anti-fraction bearing 18 supported in the counterweight portion IQ of the crank shaft. The connecting member I1 is provided with a pair of disks 2B eccentric of the crank pin IS, the

disks being oriented 180 from each other with respect to the crank pin axis. Each disk 20 is received in the aperture of a block 22 supported for rectilinear movement only by-a pair of guide rods 23 having their ends fixed to the casing Ill, each pair of guide rods being arranged at right angles to the other pair.

The connecting member 11 includes a hollow cylindrical head 24 screw-threaded and keyed to the remainder thereof, said head being concentric with the crank pin. The head 24 extends beyond one cheek of the crank shaft and is of sufficient interior diameter to clear said cheek. In the head is provided a diametrical slot 25 and a circular cap 26 is detachably connected to the end of the head by suitable bolts.

Cylindrical members 21 surrounding the head 24 are rotatably supported in the casing concentric with the crank shaft with their adjacent edges in contact. One of the cylindrical members is journalled by anti-friction bearings on a hub 28 while the other is journalled by anti-friction bearings supported by counterweight I6. A cylindrical sealing band 29 overlies the cylindrical members 21 and at each edge of the said band a ring 30 snugly surrounds one cylindrical member 21 to form an annular channel. Each cylindrical member is provided with a flange 3| extending around and beyond the ring 30 to form a continuation of the wall of said annular channel. One flange 3| slidably engages the inner face of the plate ll while the other flange slidably engages the surface lta. The sealing band 29, rings 30 and flanges 3!, together with a lining band 32 in the casing Ill constitute a ring cylinder.

Each cylindrical member 21 has an inwardly extending lug 33 adjacent one end and a counterbalancing lug 34. The lug 33 is slotted to receive the end of a block 35 which is pivotally attached thereto by a pin 33. Each block 35 lies in the slot 25 and is slidable therein. Also, each block 35 is provided with an aperture 35a of sufficient size to receive the crank shaft and permit such relative movement as is necessary for operation of the device. with ribs 351) to make the overall width of the block equal the overall Width of the lug 33.

In the ring cylinder are provided two pairs of pistons 31 and 38, one pair of pistons being fastened to one flange 3| and the other pair of pistons being fastened to the other flange 3|. To each pair of pistons is fastened the ring 30 opposite to the flange 3| fastened to said pair. In the housing are provided a pair of inlet ports Each block is provided 39 and a pair of outlet ports 40 communicating with the ring cylinder.

Rotation of the crank shaft I4 causes movement of the axis of the member I1 through a circular orbit having the crank shaft axis as its center and the member I1 is caused to rotate twice about the axis of the crank pin or once with respect to the housing in the opposite direction to the direction of rotation of the crank shaft for each revolution of the crank shaft, such rotation being effected through the interaction of the rectilinearly movable blocks 22 and the eccentric disks 25. The cylindrical members 21 are rotated by the member I1 in the same direction with it but with continuous relative rotary movement between said cylindrical members. The relative rotary movement of the members 21 results from variation in the coupling leverage between the head 24 and cylindrical members 21 through the blocks 35 and pins 36,

such variation resulting from movement of the axis of the head 24, through the orbit traversed by the crank pin with simultaneous rotation of the cylindrical members about the crank shaft axis. The pistons 31 and 38 are moved relative to each other during rotation of the members 21 to cause variation in the spacing between adjacent ends of successive pistons, thereby forming varying size chambers for the suction, compression and discharge of fluids with respect to the casing.

In the modification illustrated in Figs. 5 to 8 inclusive, the housing consists of a generally cylindrical casing I I0, closed at its ends by plates III and H2 clamped thereto by suitable bolts A crank shaft H4, having a crank pin H3. H5 is supported in the housing with the ends of the crank shaft journalled in hubs in the end plates. One cheek of the crank shaft embodies a counterweight II6 while the other cheek embodies a counterweight H9, and a detachable connection is provided between the end-of the crank pin adjacent the plate HI and the corresponding crank cheek.

A connecting member H1, provided with eccentric disks I23, is rotatably carried by the crank pin H5 and each disk is received in the aperture of a block I22 supported for rectilinear movement by a pair of guide rods I23. The crank pin II5 extends nearly the full length of the casing and the connecting member I I1 is coextensive with the crank pin. The connecting member includes a substantially rectangular head I25, the width of which is less than the diameter of the cylindrical portion of such member to provide a pair of shoulders 1a and the height of the central portion of which exceeds such diameter.

Cylindrical members I21 surrounding the head I25 are rotatably supported in the casing concentric with the crank shaft. One of the cylindrical members is journalled on a hub I28 while the other is journalled on a hub IIIa. A cylindrical sealing band I29 overlies the cylindrical members I21 and at each end of said band a ring I30 snugly surrounds one cylindrical member I21 to form an annular chamber. Each cylindrical member is provided with a flange 'I3I extending around and beyond the ring I30 to form a continuation of the wall of said annular chamber. One flange I3I slidably engages the inner face of the plate II I, while the other flange slidably engages the surface Him. The sealing band I29, rings I30 and flanges I31, together with a lining band I32 in the casing H0 constitute a ring cylinder.

A pair of elongated blocks I35 are associated with the connecting member H1. Each of the blocks has a rectangular aperture I35 through which extends the head I25, the width of the aperture being equal to the width of the head and the height of the aperture being equal to the height of the central portion of said head. One block engages the shoulder H111 and is engaged by the other block. Each block is cut away at I35" corresponding to the central portion of the head I25 to permit reciprocation of the block to a limited extent. Also, each block is provided with an arcuate bearing pad portion I35a, which is received in a recess I21a in a cylindrical member I21, the recess surface being of proper curvature to pivotally connect the pad to the cylindrical member and the remainder of the opening through the cylindrical member being of such size and shape as to permit limited relative rotary movement between the block I35 and the member I21. The arrangement of the blocks I35 on the connecting member is such that the pads I35a are diametrically opposed with respect to each other. Each member I21 is also provided with an arcuate surface I21b slidably engaged by the surface I35b of the block I35 to maintain the bearing pad I35a seated in the recesses I21a.

In the ring cylinder are provided two pairs of pistons I31 and I38, one pair of pistons being fastened to the one flange I3I and the other pair of pistons being fastened to the other flange I3I To each pair of pistons is fastened the ring I30'opposite to the flange I3I fastened to said pistons. In the housing are provided a pair of inlet ports I39 and a pair of outlet ports I40 communicating with the ring cylinder.

Rotation of the crank shaft H4 causes rotation of the member H1 and accompanying rotation of the members I21 as previously described. The relative rotary movement of the members I 21 results from variation in the coupling leverage between the connecting member H1 and the cylindrical members I21 through the blocks I35 and bearing pads I35a. The rings 30 and I30 are supported for rotation relative to the cylindrical members 21 and I21 respectively by suitable bearings.

It is of course understood that various modifications may be -made in the structure above described, without in any way departing from the I spirit of the invention as defined in the appended claims.

I claim:

1. In an apparatus of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having radial rectilinear guide means, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of cylindrical members surrounding said guide means coaxial with said crank shaft and rotatable relative thereto, a block for each cylindrical member slidably engaged with said guide means, and a pivotal connection within each cylindrical member between it and its associated block.

2. In an apparatus of the character described, a crank shaft having a crank cheek and a crank pin, a connecting member rotatably mounted on said crank pin and having a hollow cylindrical head of greater interior radius than the overall radius of said crank cheek extending beyond said crank cheek over a portion of the crank shaft, means for efiecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of rotatable members coaxial with said crank shaft, a diametrically arranged slot in said head, a block for each rotatable member slidably mounted in said slot, and a pivotal connection between each rotatable member and its associated block.

3. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross section, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess offset from its axis, and a block within each cylindrical member having an arcuate bearing pad journalled in said recess, each block having a slot slidably receiving the rectangular portion'of said connecting member.

4. An apparatus of the character described comprising a crank shaft having a crank pin. a connecting member rotatably mounted on said crank pin and having rectilinear guide means, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of cylindrical members surrounding said guide means coaxial with said crank shaft and rotatable relative thereto, a block for each cylindrical member slidably engaged with said guide means, a pivotal connection within each cylindrical member between it and its associated block, a flange on each cylindrical member having an annular face, a ring concentric with each flange and having one side lying in the same plane with said annular face, an annular chamber coaxial with said crank shaft and having each side wall composed of one 1 annular face and one ring, two pairs of pistons in said chamber, each pair of pistons being connected to one flange and the opposite ring, and inlet and outlet ports for said chamber.

5. An apparatus according to claim4 in which each ring is of lesser exterior diameter than the interior diameter of the annular flange face coplanar with one side of said ring.

6. Apparatus of the character described comprising a crank shaft having a crank pin, rotatable members coaxial with said crank shaft, a ring surrounding each rotatable member, a flange on each rotatable member concentric with said ring exterior thereof and having an annular face lying in the same plane with one face of said ring, an annular chamber coaxial with said crank shaft and having each side wall composed of one flange face and one ring face, two pairs of pistons in said chamber, each pair of pistons being connected to one flange and the opposite ring, inlet and outlet ports for said chamber, and means connecting said rotatable members to said crank shaft for effecting rotation of said members counter to the crank shaft with alternate acceleration and deceleration of said members.

'7. Apparatus of the character described comprising a crank shaft having a crank pin, rotatable members coaxial with said crank shaft, a

ring surrounding each rotatable member, a flange on each rotatable member concentric with said ring exterior thereof and having an annular face lying in the same plane with one face of said ring, an annular chamber coaxial with said crank shaft and having each side wall composed of one flange face and one ring face, two pairs of pistons in said chamber, each pair of pistons being connected to one flange and the opposite ring, inlet and outlet ports for said chamber, a connecting member rotatably mounted on said crank pin and provided with eccentric disks, means to guide each disk back and forth along a rectilinear path for effecting rotation of said connecting member twice about the crank pin for each rotation of the crank shaft and counter to the direction of rotation of said crank shaft, and interconnecting means between said connecting member and pistons for effecting rotation thereof with alternate acceleration and deceleration.

8. In an apparatus of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having radial rectilinear guide means, and one or more eccentric disks, means to guide each disc bodily back and forth along a rectilinear path, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, a block for each cylindrical member slidably engaged with the guide means of said connecting member, and a pivotal connection within each cylindrical member between it and its associated block.

9. In an apparatus of the character described, a crank shaft having a crank pin, a connecting member rotatably supported by said crank pin and having a hollow cylindrical head, one or more eccentric disks carried by said connecting member, means to guide each disk bodily back and forth along a rectilinear path, a pair of rotatable members coaxial with said crank shaft, a diametrically arranged slot in said head, a block for each rotatable member slidably mounted in said slot, and a pivotal connection between each rotatable member and its associated block.

10. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross section and one or more eccentric disks, means to guide each disk bodily back and forth along a rectilinear path, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess offset from its axis, and a block within each cylindrical member having an arcuate bearing pad journalled in said recess, each block having a slot slidably receiving the rectangular portion of said connecting member.

11. In an apparatus of the character described, a crank shaft having a crank pin, a connecting member rotatably supported by said crank pin and having a hollow cylindrical head, one or more eccentric disks carried by said connecting member, means to guide each disk bodily back and forth along a rectilinear path, a pair of rotatable members coaxial with said crank shaft, a diametrically arranged slot in said head, a block for each rotatable member slidably mounted in said slot, a pivotal connection between each rotatable member and its associated block, a flange on each rotatable member having an annular face, a ring concentric with each flange and having one side lying .in the same plane with said annular face, an annular chamber coaxial with said crank shaft having each side wall composed of one annular flange face and one ring, two pairs of pistons in each chamber, each pair of pistons being connected to one flange and the opposite ring, and inlet and outlet ports for said chamber.

12. An apparatus according to claim 11 in which each ring is of .lesser exterior diameter than the interior diameter of the annular flange face coplanar with one side of said ring.

13. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross section and one or more eccentric disks, means to guide each disk bodily back and forth along a rectilinear path, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess offset from its axis, a block within each cylindrical member having an arcuate bearing pad journalled in said recess, each block having a slot slidably receiving the rectangular portion of said connecting member, a flange on each cylindrical member having an annular face, a ring concentric with each flange and having one side lying in the same plane with said annular face, an annular chamber coaxial with said crank shaft having each side wall composed of one annular flange face and one ring, two pairs of pistons in each chamber, each pair of pistons being connected to one flange and the opposite ring, and inlet and outlet ports for said chamber.

14. An apparatus according to claim 13 in which each ring is of lesser exterior diameter than the interior diameter of an annular flange face coplanar with one side of said ring.

15. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross section and one or more eccentric disks, means to guide each disk bodily back and forth along a rectilinear path, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess ofiset from its axis and an arcuate surface opposite said recess and a block having at one end an arcuate bearing pad journalled in said recess and having its opposite end slidably engaging said arcuate surface to permit limited relative rotary movement between said block and cylindrical member while preventing relative rectilinear movement thereof, each blcck having a slot slidably receiving the rectangular portion of said connecting member.

16. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross-section, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, 2. pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess offset .from its axis, and a block within each cylindrical member having an arcuate bearing pad journalled in said recess, each block having a slot slidably receiving the rectangular portion of said connectingmember.

17. In a device of the character described, a crank shaft having a crank cheek and a crank pin, a connecting member rotatably mounted on said crank pin and having a hollow cylindrical head of greater interior radius than the overall radius of said crank cheek extending beyond said crank cheek over a portion of said crank shaft, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of cylindrical members coaxial with said crank shaft, a diametrically arranged slot in said head, a block for each rotatable member slidably mounted in said slot, a pivotal connection between each rotatable member and its associated block, a flange on each rotatable member having an annular face, a ring concentric with each flange and having one side lying in the same plane with said annular face, an annular chamber coaxial with said crank shaft having each side wall composed of one annular flange face and one ring, two pairs of pistons in each chamber, each pair of pistons being connected to one flange and the opposite ring, and inlet and outlet ports for said chamber.

18. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross-section, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess offset from its axis, a block within each cylindrical member having an arcuate bearing pad journalled in said recess, each block having a slot slidably receiving the rectangular portion of said connecting member, a flange on each rotatable member having an annular face, a ring concentric with each flange and having one side lying in the same plane with said annular face, an annular chamber coaxial with said crank shaft having each side wall composed of one annular flange face and one ring, two pairs of pistons in each chamber, each pair of pistons being connected to one flange and the opposite ring, and inlet and outlet ports for said chamber.

19. In a device of the character described, a crank shaft having a crank pin, a connecting member rotatably mounted on said crank pin and having a portion of substantially rectangular cross-section, means for effecting rotation of said connecting member twice about said crank pin opposite to the direction of crank shaft rotation for each rotation of the crank shaft, a pair of cylindrical members coaxial with said crank shaft and rotatable relative thereto, each cylindrical member having an internal arcuate recess offset from its axis and an arcuate surface opposite said recess and a block having at one end an arcuate bearing pad journalled in said recess and having its opposite end slidably engaging said arcuate surface to permit limited relative rotary movement between said block and cylindrical member while preventing relative rectilinear movement thereof, each block having a slot slidably receiving the rectangular portion of said connecting member.

CHARLES BANCROFI. 

